1. Field of the Invention
The present invention relates to a technique of transmitting video through a network.
2. Description of the Related Art
A technique of wirelessly mirroring a display screen has been standardized as Wi-Fi Miracast™ by Wi-Fi Alliance®. Mirroring is a technique of sharing a screen by transmitting the display screen of a transmission side apparatus to a reception side apparatus through a network. Unlike transmission of recorded video, mirroring makes it possible to transmit, to a reception apparatus, on-screen display information (to be referred to as “OSD information” hereinafter) such as operation buttons to be superimposed and displayed on video.
If recorded video is played back during mirroring, it becomes necessary to decode the recorded video and encode (to be referred to as “re-encode” hereinafter) a captured image. If video recording is performed during mirroring, two encoding operations (encoding of video for video recording and encoding of a captured image) are required. That is, playback of recorded video and video recording during mirroring increase the processing load. It is possible to distribute the processing load by preparing two encoders, as a matter of course. In this case, however, the cost increases.
Mirroring is different from streaming of recorded video with respect to the presence/absence of OSD information and the presence/absence of screen capturing. When, therefore, switching from mirroring to streaming of recorded video, or vice versa, it is necessary to perform a user operation of temporarily stopping one process, and then starting the other process.
Each of Japanese Patent Laid-Open Nos. 2012-133210 and 2006-236153 proposes a method of reducing the processing load and network load of mirroring. These patent literatures, however, do not disclose any method of preventing the processing load from increasing due to video recording and playback of recorded video during mirroring.